Method for patterning dielectric layers on semiconductor substrates

ABSTRACT

The invention relates to a process for patterning dielectric layers. A photoresist layer is applied to the dielectric layer and patterned. Then, the pattern which has been predetermined by the resist mask is transferred to the dielectric layer. The incineration of the resist mask is carried out a temperature of 50° C. to 200° C., with the oxygen plasma being generated from a gas which has an oxygen content of 40 to 60% by volume. During a subsequent step of cleaning the patterned dielectric layer using dilute hydrofluoric acid, the trenches which have been introduced into the dielectric layer are widened to a significantly lesser extent than after incineration under the conditions which have previously been customary.

BACKGROUND

1. Field of the Invention

The invention relates to semiconductor memory devices and, moreparticularly, to a method for patterning dielectric layers onsemiconductor substrates to produce contact holes or trenches in thedielectric layer.

2. Background Information

To continue increasing the power of microprocessors and memory chips, itis necessary for the dimensions of the individual microelectroniccomponents, such as capacitors or transistors, to be constantly reducedfurther. This allows a higher integration density to be achieved on agiven chip surface area and also allows the operations carried out perunit time to be shortened. To enable the integration density to befurther increased, different microelectronic components are increasinglybeing stacked on top of one another in layers. To allow the individualmicroelectronic components in each case to be driven in a controlledmanner, therefore, it is necessary to use a plurality of interconnectlevels that are arranged above one another and are in each case isolatedfrom one another by insulating dielectric layers.

During production of a microchip, the structures of the individualcomponents are generally produced by sequential deposition of layers ofdifferent materials. To allow targeted processing of sections of theselayers, masks are produced from a photosensitive resist that can bepatterned using lithography methods. After the exposed photoresist hasbeen developed, during which step certain sections of a layer of thephotoresist are removed selectively, sections of the layer arrangedbeneath the resist mask are uncovered and can then be processedselectively. After the processing step, the resist mask is removedagain. For this purpose, the resist mask can, for example, be dissolvedusing a suitable solvent or incinerated in an oxygen plasma. This isgenerally followed by a wet-chemical cleaning step in order to removeresidues of organic materials and oxide layers that were formed in theoxygen plasma from the surface.

During the production of a contact hole, through which a conductiveconnection is to be produced between an electronic component arranged ina lower level, such as the source contact of a transistor, and aninterconnect arranged in a higher level, the procedure has hithertobeen, in the most simple case, for an insulating dielectric layer to bedeposited on the level which comprises the contact of an electroniccomponent and to which a conductive connection is to be produced. Alayer of a photosensitive resist is deposited on this dielectric layer,and the resist layer is then exposed in sections and developed in aconventional manner such that the dielectric layer is uncovered in thesection in which the contact hole is to be introduced. Then, the contacthole is etched into the dielectric layer using a suitable plasma, forexample, a fluorine-containing plasma, so that the contact to themicroelectronic component is uncovered at the base of the contact hole.

Next, the resist film or resist mask is incinerated in an oxygen plasma.The incineration is carried out at a temperature of approximately 250°C. within approximately 1 to 1.5 minutes. The oxygen plasma is generatedfrom a gas mixture which substantially comprises oxygen and to whichsmall quantities of a forming gas have been added. The forming gasserves to stabilize the plasma and usually consists of a mixture ofnitrogen gas and hydrogen gas. The proportion of the forming gas in thegas for generating the oxygen plasma is generally selected to be between3 and 10% by volume, usually in the region of approx. 5% by volume. Thisis followed by wet-chemical cleaning of the patterned surface of thedielectric layer under oxidizing conditions in order to remove organicresidues adhering to the surface. An example of a standard cleaningagent is H₂SO₄ in combination with O₃.

The contact that is uncovered at the base of the contact hole usuallyconsists of silicon which is provided, for example, with a doping.Therefore, a thin film of oxide is formed in the oxygen plasma or as aresult of oxygen or water from the ambient air, and this thin film ofoxide must first be removed before the contact hole is filled with aconductive material. For this purpose, the surface is cleaned usinghighly dilute aqueous hydrofluoric acid which is buffered, for example,with NH₄F. However, this removes not only the oxide layer at the base ofthe contact hole, but also material on the side walls of the contacthole. Therefore, the cleaning with buffered hydrofluoric acid widens thestructures which have been etched into the dielectric layer. The sameproblem arises if the contact is composed of a metallic layer, forexample for producing Vias between interconnect levels arranged aboveone another. In this case too, an oxide layer is formed on the surfaceof the contact and must firstly be removed before the contact hole isfilled. Hydrofluoric acid can be used as a standard etchant for thispurpose.

With the current feature sizes that are realized in the production ofmicrochips, it is possible to control the widening by optimizing theprocess conditions for cleaning with dilute hydrofluoric acid. For thispurpose, by way of example, the concentration of the hydrofluoric acid,the temperature at which the cleaning is carried out and the duration ofthe cleaning can be optimized. Furthermore, when designing the chip itis possible to take into account the widening of the contact holes ortrenches that occurs during the cleaning using dilute hydrofluoric acid.The widening that has to be taken into account as a result of thecleaning using buffered dilute hydrofluoric acid is currently in therange from approx. 25 to 38% with respect to the etched dimension. Afurther reduction in the widening by, for example, shortening thecleaning time no longer appears possible, since in this case the oxidelayer on the contact at the base of the contact hole can no longer beremoved to a sufficient extent.

Future chip technology will require the production of a critical featuresize in the region of 90 nm or below. In this case, it is no longerpossible to take account of the widening of the contact holes which areintroduced into a dielectric layer when designing the microchip. Sincethe widening of the contact holes is independent of the diameterthereof, i.e. becomes ever more pronounced as the feature size isreduced, it is imperative to find ways of producing contact holes withthe required high level of accuracy even for a critical feature size ofless than 90 nm.

SUMMARY

Embodiments of the invention are described for providing a process forpatterning dielectric layers on semiconductor substrates that enableproduction of contact holes or trenches in the dielectric layer with ahigh level of accuracy, even for small dimensions.

A method is described for patterning dielectric layers on semiconductorsubstrates. A first layer is provided, and at least one layer formedfrom a dielectric is deposited on the first layer, so that a dielectriclayer is obtained. A photosensitive resist layer is deposited on thedielectric layer. The resist layer is exposed and developed in sections,so that a resist mask is obtained, through which sections of thedielectric layer are uncovered. The dielectric layer is removed in thesections which have been uncovered through the resist mask at least downto a depth which is such that the first layer is uncovered.

In one embodiment of the invention, the resist mask is incinerated in anoxygen plasma, the incineration being carried out at a temperature whichis selected to be approximately 200° C. or lower. In another embodiment,the oxygen plasma is generated from a gas which at least contains oxygengas and a forming gas, the oxygen gas being present in an amount ofapproximately 60% or less by volume and the forming gas being present inan amount of approximately 40% or more by volume, so that a patterneddielectric layer is obtained. In a further embodiment, the patterneddielectric layer is cleaned using aqueous dilute hydrofluoric acid.

The invention is explained in more detail below with reference todiagrammatic drawings on the basis of preferred exemplary embodiments ofthe methods according to the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is explained in more detail below with reference to theappended drawings, in which, in detail:

FIGS. 1A–1E illustrate steps involved in carrying out a process forpatterning dielectric layers according to an embodiment of the presentinvention;

FIGS. 2A–2E illustrate steps involved in carrying out the process ofFIG. 1 with the dielectric layer comprising a plurality of layers;

FIG. 3 is a graph illustrating an amount of a dielectric materialremoved after a treatment in the oxygen plasma and after a cleaning withbuffered hydrofluoric acid.

DETAILED DESCRIPTION

It has been found that the widening of the holes or trenches introducedinto the dielectric layer, which is observed during the final cleaningstep using aqueous dilute hydrofluoric acid, can be influenced by theconditions under which incineration of the resist mask is carried out.Optimizing the conditions for the incineration of the resist mask makesit possible to reduce the extent to which the trenches or holes whichhave been introduced into the dielectric layer are widened. Therefore,the process according to the invention makes it possible to producecontact holes or trenches with a high level of accuracy and with asmaller diameter than can be achieved with the processes which arecurrently customary.

FIG. 1A shows a layer 1 comprising a dielectric into which aninterconnect 2 has been introduced. The interconnect 2 is composed, forexample, of aluminum and forms the first layer in the context of theinvention. A further dielectric layer 3, which consists, for example, ofsilicon dioxide and into which a contact hole is to be introduced inorder to produce a Via, is arranged on the layer 1.

As illustrated in FIG. 1B, a photosensitive layer 4 is applied to thedielectric layer 3, exposed and developed, in order to define an opening5, which serves as a mask for the production of the contact hole. Then,as shown in FIG. 1C, a contact hole 6 is etched through the dielectriclayer 3 in a conventional manner using a fluorine-containing plasma,extending as far as the interconnect 2. In the next working step, thephotosensitive layer 4 is incinerated in an oxygen-containing plasma.Typical incineration conditions are given below:

-   Temperature: 195° C. (50° C.–200° C.)-   Oxygen: 1 000 sccm (<2 000 sccm)-   O₂/forming gas ratio: 1/1 (V/V)-   Forming gas: 1 000 sccm-   Treatment duration: 50 s

As illustrated in FIG. 1D, the top side of the dielectric layer 3 isuncovered again and an oxide layer 7 forms on the uncovered surface ofthe interconnect 2 at the base of the contact hole 6. The oxide layer 7can be removed using dilute hydrofluoric acid. The contact hole 6 isonly slightly widened in the process. Then, the contact hole 6 is filledwith a conductive material in the usual way, and after this a furtherinterconnect 8 is deposited, as shown in FIG. 1E. The interconnects 2and 8 are electrically conductively connected by a Via 9.

FIG. 2 shows steps that are involved in carrying out the processaccording to embodiments of the invention. As can be seen, thedielectric layer 3 comprises a plurality of layers made from differentmaterials. FIG. 2A shows a semiconductor layer 10, for example a siliconwafer, in which a doped region 11, to which a conductive connection isto be produced, is defined. A dielectric layer 3 composed of a pluralityof individual layers is arranged on the semiconductor layer 10. With thearrangement illustrated in FIG. 2A, first a layer 12 of aborophosphosilicate glass (BPSG) is deposited on the semiconductor layer10. A silicon carbide layer 13 is deposited on this layer 12. Moreparticularly, this layer 13 substantially comprises silicon carbide witha high hydrogen content produced by chemical vapor deposition. Finally,the top layer provided is a silane oxide layer 14, which is produced bychemical vapor deposition, for example from silicon tetrachloride andwater.

To enable a conductive connection to the doped region 11 to be produced,it is necessary for the section in which a contact hole extendingthrough the dielectric layer 3 is to be introduced to be defined on thesurface of the dielectric layer 3. For this purpose, first a layer of aphotosensitive resist 4 is applied, selectively exposed and thendeveloped in a conventional manner. The result, as illustrated in FIG.2B, is a resist mask that comprises an opening 5 in which the surface ofthe dielectric layer 3 is uncovered. The area that is predetermined bythe opening 5 is then etched through the dielectric layer 3 using afluorine-containing plasma, so that a contact hole 6 is obtained,extending through the dielectric layer 3 to the doped region 11 of thesemiconductor layer 10. Then, the photosensitive layer 4 is removed byincineration in the oxygen plasma. The incineration can be carried outunder the conditions given for FIG. 1.

After the incineration of the photosensitive layer 4 in the oxygenplasma, the surface of the dielectric layer 3 has been uncovered again.At the same time, however, a thin film of oxide 7 forms at the base ofthe contact hole 6, as illustrated in FIG. 2D. If the contact hole 6were to be filled directly with a conductive material, the oxide film 7would lead to a high resistance. It is therefore necessary for the oxidefilm 7 first to be removed by means of treatment with dilute aqueoushydrofluoric acid. For this purpose, aqueous hydrofluoric acid is addedto the arrangement illustrated in FIG. 2D (dilution: 1:500; roomtemperature (23° C.); 30–60 s). The oxide layer 7 is dissolved. At thesame time, however, the dilute hydrofluoric acid attacks the side wallsof the contact hole 6 which are formed by the dielectric layer 3.However, the extent to which the contact hole 6 is widened issignificantly less than after incineration of the photosensitive layer 4under the conditions which have hitherto been customary. After the oxidelayer 7 has been removed, the contact hole 7 is filled with a conductivematerial 15 in order, as illustrated in FIG. 1E, to produce a conductiveconnection extending through the dielectric layer 3 to the doped region11 in the semiconductor layer 10.

The influence of the incineration conditions on the removal of thedielectric layer can be demonstrated by the following examples.

Blank silicon wafers as semiconductor material are coated with a siliconcarbide layer of a certain layer thickness. A layer of a photoresist isapplied to this silicon carbide layer. The photoresist is thenincinerated using an oxygen plasma. The conditions given in Table 1 areset in this case. The incineration is carried out in different plasmachambers (plasma chambers A and B) and at different temperatures andoxygen concentrations. After the incineration of the photoresist layer,the layer thickness of the silicon carbide layer is determined, and thelayer thickness loss caused by the incineration is calculated from thedifference. The layer thickness loss is represented in FIG. 3 a in theform of a bar chart. It can be seen that during the incineration theremoval of the silicon carbide layer is influenced by the temperatureand by the oxygen concentration in the plasma. However, no clear trendcan be determined. The removal of material from the layer is influencednot only by the temperature and the oxygen concentration but also, forexample, by the type of plasma chamber used.

Then, all the wafers are treated under identical conditions with adilute aqueous buffered hydrofluoric acid (H₂O/HF=500:1; 23° C.; 60 s).After the treatment, the layer thickness of the silicon carbide layer isdetermined again, and the further layer thickness loss is calculatedtherefrom. The further layer thickness loss is illustrated in FIG. 3B.It can be seen that the silicon wafers which have been treated using theprocess according to the invention are subject to significantly lesslayer thickness loss during the treatment with dilute hydrofluoric acidthan silicon wafers on which the incineration takes place at highertemperatures and/or at higher oxygen concentrations. The overall loss oflayer thickness is determined by adding together the values from FIG. 3Aand FIG. 3B. It can be seen that when the process according to theinvention is being carried out, the layer thickness loss is considerablylower than after incineration under the conditions which have hithertobeen customary. This means that contact holes or trenches can beintroduced into a dielectric layer with a significantly smallerdiameter, since significantly reduced widening of the opening isobserved during the cleaning using dilute aqueous hydrofluoric acid.

The process conditions used to incinerate the photoresist layer aregiven in Table 1 below.

TABLE 1 Reaction conditions for the incineration of the resist layerPlasma Temperature N₂/H₂ Wafer chamber (° C.) O₂ (sccm) 1:1 (sccm) 1 A250 4000 200 2 B 250 4000 200 3 B 195 4000 200 4 B 195 1000 1000 5 B 1951000 1000

The process according to the invention is fundamentally suitable for anydesired dielectric materials. In addition to the materials siliconcarbide (SiC(H)), BPSG (borophosphosilicate glass) and silane oxidewhich have already been described, the process is also suitable, forexample, for patterning TEOS (tetraethylene orthosilicate), thermaloxides, phosphorus-doped silicon glass, FSG (fluorinated silicateglass), SiC(N), SiOC and similar compounds as well as inorganic low Kmaterials.

Thus, when carrying out the method according to the invention, theprocedure is that first a first layer is provided. This first layer may,for example, be a semiconductor layer which, for example, comprisesdoped regions, and contact is to be produced between these regions andan interconnect level. The semiconductor layer generally consists ofsilicon which may, for example, be provided for the purpose of producinga source or drain contact of a transistor having a doping. The firstlayer may also be formed by a semiconductor substrate into which atrench is to be introduced, for example for the fabrication of a trenchcapacitor. Furthermore, the first layer may also be composed of a metaland be designed, for example, as an interconnect, to which contact is tobe produced, for example as a Via leading to an interconnect levelarranged higher up.

At least one layer of an insulating material is then deposited on thisfirst layer, so that a dielectric layer is obtained. The dielectriclayer may comprise a single layer which is formed homogeneously from asingle material. However, it is also possible for a plurality of layersof in each case different dielectric materials to be arranged above oneanother, and these layers together then form the dielectric layer intowhich a contact hole is to be introduced, extending as far as the firstlayer. The dielectric layer is deposited using standard processes, forexample by chemical vapor deposition (CVD). The insulating materialsused may inherently be all customary materials. Typical examples includeoxide layers, in particular layers of silicon dioxide, or else layerscomprising a silicate glass, for example a borophosphosilicate glass.

To define the area of the dielectric layer that is to be removed for theproduction of a trench or a contact hole, a layer of a photosensitiveresist is deposited on the dielectric layer. It is possible to useconventional photoresists, as are customarily used in the fabrication ofmicrochips. The photosensitive resist layer is likewise deposited usingconventional methods, for example by spin-on processors. Thephotosensitive resist layer is then exposed in the usual way, in whichcase a section of the resist film which corresponds to the contact holeis exposed, for example with the aid of a photomask. The resist layer isthen developed in the usual way, so that a resist mask is obtainedcomprising sections in which the dielectric layer is uncovered.

The dielectric layer is then removed in the uncovered sections until thefirst layer, arranged beneath the dielectric layer, is uncovered again.The dielectric layer may in this case be removed down to the boundarysurface between dielectric layer and first layer. However, it is alsopossible for the removal of material to continue into the first layer,in order, for example, to produce a trench in the first layer. Thedielectric layer is removed using standard processes. Generally, asuitable plasma is used. If the dielectric layer consists, for example,of silicon dioxide, the contact hole can be etched, for example, using afluorine-containing plasma.

When the contact hole has been introduced into the dielectric layer,according to the invention the conditions during the incineration of theresist mask in an oxygen plasma are then selected in such a way that theincineration is carried out at a lower temperature than with theprocesses which are currently customary. According to the invention, thetemperature for the incineration is selected to be lower than 200° C.,preferably between 50° C. and 200° C.

Furthermore, the incineration is carried out at a lower oxygenconcentration than that which is used in the incineration steps thathave previously been customary. During the incineration which haspreviously been customary, the proportion of oxygen gas in the gas forgenerating the oxygen plasma is usually selected to be higher than 90%by volume. By contrast, in the process according to the invention theproportion of oxygen in the gas for generating the oxygen plasma isselected to be lower. The oxygen content is suitably selected to be lessthan 60% by volume, preferably between 40% by volume and 60% by volume,particularly preferably between 40% by volume and 50% by volume. Theproportion of forming gas is selected to be correspondingly higher. Theforming gas does not directly participate in the incineration of theresist but does stabilize the plasma. In the method according to theinvention, the proportion of the forming gas is suitably selected to begreater than 40% by volume, preferably between 60 and 40% by volume,particularly preferably between 60 and 50% by volume.

After the resist mask has been incinerated, the result is a patterneddielectric layer into which, by way of example, contact holes ortrenches are introduced, extending through the dielectric layer to thefirst layer arranged beneath the dielectric layer. Finally, cleaning iscarried out using dilute hydrofluoric acid in order to remove an oxidelayer which has formed on the first layer at the base of the contacthole or of the trench. This step fundamentally uses the same conditionsas have also previously been customary for cleaning of the patterneddielectric layer after resist incineration. The concentration of thedilute aqueous hydrofluoric acid HF/H₂O is generally between 1:300 and1:500. The cleaning is usually carried out at room temperature and for aduration of between 10 seconds and 120 seconds.

Surprisingly, the contact holes or trenches are widened to asignificantly lesser extent than after incineration of the resist layerunder the conditions which have hitherto been customary, i.e. withincineration of the photosensitive layer at a high temperature and/orusing a plasma with a high oxygen content. Therefore, in addition to thetemperature, the duration and the concentration of the aqueoushydrofluoric acid, which are in each case selected during the cleaningusing hydrofluoric acid after the incineration of the resist mask, theprocess according to the invention provides a further parameter whichcan be used to influence the widening of a contact hole or a trenchduring the cleaning using aqueous hydrofluoric acid, namely theconditions for the incineration of the resist mask.

After the contact hole or trench has been introduced into the dielectriclayer and the final cleaning has taken place, the patterned dielectriclayer is processed in the usual way. By way of example, a liner whichcovers the side walls can be introduced into the trench or contact hole,or the contact hole may, for example, also be filled directly with aconductive material.

The duration of time required to incinerate the resist mask is selectedto be as short as possible, in order to minimize damage to the sidewalls of the trench or the contact hole. A duration of between 30seconds and 120 seconds is suitably selected for the incineration of theresist mask, particularly preferably a duration of between 30 secondsand 60 seconds. The duration selected for the incineration is influencedby the resist material and by the thickness of the resist layer.However, the person skilled in the art can readily determine anappropriate duration for the incineration of a given resist materialwith a given layer thickness by means of simple preparatory tests.

In the process according to the invention, the incineration of theresist mask is carried out at an oxygen concentration which issignificantly lower than with processes which have hitherto beencustomary. The oxygen partial pressure in the gas for generating theoxygen plasma is appropriately selected to be between 0.2 and 8.0 Torr,particularly preferably between 0.8 and 1.5 Torr.

In addition to the oxygen gas, the gas for generating the oxygen plasmaalso contains a forming gas as a further constituent. The forming gasused may, for example, be nitrogen gas. However, it is preferable forthe forming gas to contain at least nitrogen gas and hydrogen gas.

The forming gas generally contains the nitrogen gas in excess withrespect to the hydrogen gas. The hydrogen gas content in the forming gasis suitably selected to be between 1 and 50% by volume.

The first layer may inherently consist of any desired material. However,it is appropriate to use materials which form water-soluble fluorides.The first layer is particularly preferably composed of silicon. Duringthe incineration of the resist layer, first of all a thin film ofsilicon dioxide is formed on the semiconductor layer which has beenuncovered at the base of the contact hole, and this thin film of silicondioxide can be removed using dilute hydrofluoric acid. The silicon mayalso comprise a doping which, for example, increases the electricalconductivity. Doped regions of this type are used, for example, assource or drain contact for field-effect transistors.

As has already been described above, the dielectric layer may inherentlybe composed of any desired materials which allow a sufficient insulatingaction to be achieved between different electrically conductive levels.However, the effect which is observed with the method according to theinvention is particularly pronounced in the case of dielectrics whichare derived from silicon. Therefore, the dielectric layer particularlypreferably comprises at least one layer made from a silicate glassand/or a silicon carbide. The silicate glass used may, for example, besilicon dioxide. However, the silicate glass may also contain furtherelements, for example boron or phosphorus. The silicate glass isdeposited using standard processes, for example by chemical vapordeposition. In addition to silicon and carbon, the silicon carbide mayalso comprise other elements, in particular hydrogen. A silicon carbidewith a high proportion of hydrogen atoms can be produced, for example,by chemical vapor deposition.

The final cleaning of the patterned dielectric layer is carried outusing dilute aqueous hydrofluoric acid. It is fundamentally alsopossible to select other solvents in which the hydrofluoric acid issoluble. However, since it is easier to dispose of, it is preferable touse an aqueous dilute hydrofluoric acid. The concentration of thehydrofluoric acid is selected to be as low as possible, in order toallow the treatment times to be controlled with sufficient accuracy andin order to ensure that the minimum possible amount of the dielectriclayer is removed at the side walls of the trench or the contact hole.The aqueous dilute hydrofluoric acid appropriately contains HF and H₂Oin a ratio of less than 1:400, preferably less than 1:500.

For the final cleaning of the patterned dielectric layer, the treatmenttime is selected to be as short as possible, in order to avoidoveretching. It is preferable for the duration of the cleaning of thepatterned dielectric layer using dilute hydrofluoric acid to be selectedto be less than 60 seconds, particularly preferably less than 30seconds.

The cleaning step in which the patterned dielectric layer is treatedwith hydrofluoric acid inherently corresponds to the standard cleaningmethod. The dilute hydrofluoric acid usually contains a buffer salt,particularly preferably NH₄F.

As with the processes which have hitherto been customary, in the processaccording to the invention too wet-chemical cleaning can be carried outfirst of all after the incineration of the resist mask, in order toremove organic residues which have remained on the patterned dielectriclayer after the incineration of the resist mask. The wet-chemicalcleaning is generally carried out under oxidizing conditions. Standardprocesses, for example, as described above, a treatment with H₂SO₄/O₃,can be used for this purpose.

The foregoing disclosure of embodiments of the present invention hasbeen presented for purposes of illustration and description. It is notintended to be exhaustive or to limit the invention to the precise formsdisclosed. Many variations and modifications of the embodimentsdescribed herein will be obvious to one of ordinary skill in the art inlight of the above disclosure. The scope of the invention is to bedefined only by the claims appended hereto, and by their equivalents.

Further, in describing representative embodiments of the presentinvention, the specification may have presented the method and/orprocess of the present invention as a particular sequence of steps.However, to the extent that the method or process does not rely on theparticular order of steps set forth herein, the method or process shouldnot be limited to the particular sequence of steps described. As one ofordinary skill in the art would appreciate, other sequences of steps maybe possible. Therefore, the particular order of the steps set forth inthe specification should not be construed as limitations on the claims.In addition, the claims directed to the method and/or process of thepresent invention should not be limited to the performance of theirsteps in the order written, and one skilled in the art can readilyappreciate that the sequences may be varied and still remain within thespirit and scope of the present invention.

1. A method for patterning dielectric layers on semiconductorsubstrates1 comprising at least the steps of: providing a first layer;depositing at least one layer formed from a dielectric on the firstlayer, so that a dielectric layer is obtained; depositing aphotosensitive resist layer on the dielectric layer; exposing anddeveloping the photosensitive resist layer in sections, so that a resistmask is obtained, through which sections of the dielectric layer areuncovered; removing the dielectric layer in the sections which have beenuncovered through the resist mask at least dawn to a depth which is suchthat the first layer is uncovered; incinerating the resist mask in anoxygen plasma, the incineration being carried out at a temperature whichis selected to be approximately 2000° C. or lower, and the oxygen plasmabeing generated from a gas which at least contains oxygen gas and aforming gas, the oxygen gas being present in an amount of betweenapproximately 60% and 40% volume and the forming gas being present in anamount of between approximately 40% and 60% volume, so that a patterneddielectric layer is obtained , the incinerating minimizing total lost ofthe patterned dielectric layer in a subsequent step of cleaning; andcleaning the patterned dielectric layer using aqueous dilutehydrofluoric acid.
 2. The method of claim 1, wherein the duration of thestep of incinerating the resist mask is selected to be between 30 s and120 s.
 3. The method of claim 1, wherein the oxygen partial pressure inthe gas for generating the oxygen plasma is selected to be between 0.2and 8.0 Torr.
 4. The method of claim 1, wherein the forming gas at leastcontains nitrogen gas and hydrogen gas.
 5. The method of claim 1,wherein the first layer is composed of silicon.
 6. The method of claim5, wherein the dielectric layer comprises at least one layer composed ofa silicate glass and/or a silicon carbide.
 7. The method of claim 1,wherein the aqueous dilute hydrofluoric acid has an HF/H₂O concentrationof less than 1:400.
 8. The method of claim 2, wherein the duration ofthe step of cleaning the patterned dielectric layer using dilutehydrofluoric avid is selected to be less than 60 seconds.
 9. The methodof claim 8, wherein the dilute hydrofluoric acid comprises a buffersalt.
 10. The method of claim 1, wherein a wet-chemical clean is criedout after the resist mask has been incinerated.
 11. A method forpatterning a dielectric layer on a semiconductor substrate, comprising:providing a first layer, depositing a layer formed from a dielectric onthe first layers so that a dielectric layer is obtained; depositingphotosensitive resist layer on the dielectric layer; exposing anddeveloping the resist photosensitive layer in sections, so that a resistmask is obtained, through which sections of the dielectric layer areuncovered; removing the dielectric layer in the sections which have beenuncovered through the resist mask at least down to a depth which is suchthat the first layer is uncovered; incinerating the resist mask in anoxygen plasma, the incineration being carried out at a temperature whichis selected to be approximately 200° C. or lower, and the oxygen plasmabeing generated from a gas which at least contains oxygen gas and aforming gas, the oxygen gas being present in an amount of betweenapproximately 60% and 40% by volume and the forming gas being present inan amount of between 40% and 60% by volume, so that a patterneddielectric layer is obtained the incinerating minimizing total lost ofthe patterned dielectric layer in a subsequent step of cleaning; andcleaning the patterned dielectric layer using aqueous dilutehydrofluoric acid.
 12. The method of claim 11, wherein the duration ofthe step of incinerating the resist mask is selected to be between 30 sand 120 s.
 13. The method of claim 11, wherein the oxygen partialpressure in the gas for generating the oxygen plasma is selected to bebetween 0.2 and 8.0 Torr.
 14. The method of claim 11, wherein theforming gas at least contains nitrogen gas and hydrogen gas.
 15. Amethod for patterning a dielectric layer on a semiconductor substrate toform contact holes, comprising: providing a first layer; depositing atleast one layer formed from a dielectric on the first layer, so that adielectric layer is obtained, wherein the dielectric layer is selectedfrom the group consisting of silicon glass and silicon carbide;depositing a photosensitive resist layer on the dielectric layer;exposing and developing the photosensitive resist layer in sections, sothat a resist mask is obtained, through which sections of the dielectriclayer are uncovered; removing the dielectric layer in the sections whichhave been uncovered through the resist mask at least down to a depth toexpose first layer; and incinerating the resist mask in an oxygenplasma, the incineration being carried out at a temperature which isselected to be approximately 200° C. or lower, and the oxygen plasmabeing generated from a gas which at least contains oxygen gas and aforming gas, the oxygen gas being present in an amount of betweenapproximately 60% and 40% by volume and the forming gas being present inan amount of between 40% and 60% by volume, so that the patterneddielectric layer is so that a patterned dielectric layer is obtained toform a contact hole, the incinerating minimizing total lost of thepatterned dielectric layer in a subsequent step of cleaning and cleaningthe patterned dielectric layer using dilute hydrofluoric acid.
 16. Themethod of claim 15, wherein the oxygen gas being present in an amount ofbetween approximately 50% and 40% by volume and the forming gas beingpresent in an amount of between approximately 50% and 60% by volume, sothat the patterned dielectric layer is obtained.
 17. The method of claim16, wherein the oxygen partial pressure in the gas for generating theoxygen plasma is selected to be between 0.2 and 8.0 Torr.
 18. The methodof claim 16, wherein the forming gas at least contains nitrogen gas andhydrogen gas.
 19. The method of claim 5, wherein the dielectric layercomprises at least one layer composed of a silicate glass and/or asilicon carbide.